cannot open source file stdafx.h or <stdafx.h>
Yes I understand what precompiled headers are
I have been struggling the past hour trying to get a precompiled header stdafx.h to my project as I'm getting the error:
"cannot open source file "stdafx.h".
I tried the Precompiled Header list under Project/Properties and tried making a new temporary project that other suggestions say to just copy from there, but the only ones I see come in <iostream> instead
I've read every other solution here and I'm frustrated why its still not working.
In my header file, it says its using stdafx.h, and I tried both "don't use a precompiled header" and the one I've been suggested through guides. Just want my stdafx.h in my code to work.
Followed past posts here in the past(latest 2016)
changed precompiled header list and tested/messed with the options following suggestions
Tried creating a temporary file pulling the header from there, it wasn't there.
Related
I am trying to introduce precompiled headers into my project because of long compile times in my project right now. I have a main project that includes a main function and all the real code is in the DLL project(they are linked together.) I named my precompiled header "vpch.h" and i created a vpch.cpp that includes vpch.h. I am using visual studio 2017 so I went into the properties of vpch.cpp and selected Create. Then I added vpch.h as the first thing in all my cpp files. All files are set to use precompiled headers and reference vpch.h Every CPP files throws the error:
Error C1010 unexpected end of file while looking for precompiled header.
Did you forget to add '#include "vpch.h"' to your source?
I am at a loss as to what to do because I have followed many tutorials and can't find a reason for this. As well as most issues that pop up on google are people just accidentally including precompiled headers.
My only thought is that maybe in the section in properties where it asks for the name of the precompiled header, I need to do more than put "vpch.h" and maybe an exact file location? Any help with this is super appreciated.
EDIT
From further debugging it would appear that all but ONE cpp file is throwing an error. The one that doesn't throw an error is the one that exists in the same exact folder as the vpch.h. So files that can't just write #include "vpch.h" and have to write something like "../vpch.h" I can write #include <vpch.h> and I am going to try that now but I am unsure that will help.
The issue was with every CPP file that wasnt in the same folder as the precompiled header.
So if you use a file structure that contains different classes in different folders, using
#include "../../vpch.h" will actually fail. You must add the root folder to your additional include directories and then use #include <vpch.h> for all files. I can NOT tell you why using #include "../../vpch.h" wasn't working. It seems counter intuitive for it to fail in my opinion.
It may be because it searches for the precompiled header in the same folder as the file you are referencing it in. This answer, however, will work as a solution.
So I have been trying to learn cpp and I was writing a program, and when I try to build the solution, it gives an error saying
unexpected end of file while looking for precompiled header. Did you forget to add #include "pch.h" to your source?
Then I included it and I got the same error, and also another saying
cannot open source file pch.h
One option, if you are new to c++, is to just turn off pre-compiled headers in the project settings.
It needs to be the first include, you can't place it under other includes.
Your .cpp file is probably not in the same directory as pch.h
Try adding the directory that your pch.h is in to the additional includes, even if it is at the root of your project.
quick solution to a frustrating issue when trying to add .pch to an exisiting project:
if you have a /include /src dir structure, it might not work,
unless you place the "pch.h" and "pch.cpp" in the same dir /src.
Also: mark the "MyPreComp.cpp" as /Yc - create,
and in the .cpp files you want to use the .pch set them to Yu - use.
#include "pch.h" as the first #include in the .cpp
NB. You need to set "not using precompiled headers" to all .cpp files not using them,
yes, it IS a hassle.
( Visual Studio 2019 )
It needs to be included to each cpp file (by default)
It needs to be included in the very first line of your code (excluding the comments, it's ok to have the fancy comments on top)
It needs to be in a reachable directory. This error often happen when you have a folder structure in your project. So this can happen with a source files in some nested folder, when your precompile-header-file is up there in main. In this case, either add necessary number of "../" before the file name, or add the main folder to the "additional include directories" as it is already suggested above.
It needs to actually be the same precompile header file, that is set as the one in project setting. Check the file with "Precompiled Header" option set to "Create (/Yc)", ensure that it refers to he same header file, that you include ("pch.h" or "stdafx.h" by default) This error often happens when you include some old source to newer proj, or vice-versa, due to different default names in different studio versions: "stdafx.h" vs "pch.h".
If all above is set up, and you still have it, check if you actually set it up for the right build configuration. Always apply project setting change for all configurations. Costed me some nerves when I did it for only one config, and was trying to compile another:
I understand what precompiled headers are doing with "#include "StdAfx.h" and yes, I know I can turn them off. But that's not my question.
If you're using precompiled headers, Visual C++ requires every cpp file to #include "StdAfx.h", even the files that aren't using any of the headers in StdAfx.h. If you forget to include StdAfx.h on one file, it's an error. But why? The obvious approach would be just "If you include StdAfx.h then that file will use it, but if you forget to include it, then those header files will simply not be included." I don't understand why VC++ would require you to include StdAfx.h when it's not needed. Seems like it would have been easier for them to treat it like a normal header file.
Is there any good reason why this is required?
Just a addition to the Marks answer. In fact, you do not have to manually include stdafx.h in the all project source files. You may use project option Forced Include Files:
That way stdafx.h will be automatically included in all your sources.
Your project default is "use precompiled headers". You can set individual files to "not use precompiled headers" if you desire.
In fact, stdafx.cpp itself has a different option from the project defaults:
What this configuration is saying is "start compiling this file (stdafx.cpp), stop when you finish compiling the statement that includes stdafx.h" and save the precompiled information as as .pch file." Visual studio is also smart enough to compile this file first so it is available for use.
The project defaults are:
What this configuration is saying is "For each compiled file, start with the precompiled data in the specified .pch and start compiling new information after the point stdafx.h is included." That's important and why stdafx.h should be included as the first line of the file. It will still work if you put it later in the file, but anything before the #include is ignored because that data won't be in the .pch. Absence of the #include means VS will scan the whole file looking for the pre-compiled starting location and not find it...generating an error.
If you have a file that you don't want to use pre-compiled information, you can select the file and override it. Example:
Visual Studio won't use the precompiled information and won't look for a header to include.
When you select the file, right-click properties, go to the "C/C++ \ Precompiled Headers" section and set "Precompiled Header" to "Not using Precompiled Headers", be sure that the Configuration (top left) is applicable to the current selected build.
It doesn't always automatically select the "active" configuration; so you could be setting the option for a non-active configuration so you will continue to experience the error ;)
I've been handed the source code for a very large c++ project and asked to make a small change to support some new hardware. I'm not very familiar with c++, as I mostly use C# these days.
When I built the project I'm getting 20+
Error 2 error C1083: Cannot open include file: 'StdAfx.h': No such file or directory D:.. thefile.cpp
From my understanding the "StdAfx.h" is to do with precompiled headers, and is automatically generated?
I followed the answer on this question:
1 Ensure you have the file "stdafx.h" in your project. If you don't
(e.g. you removed it) just create a new temporary project and copy the
default one from there;
but in doing so noticed that the created stdafx.h file doesn't have the capitalisation of the referenced "StdAfx.h"
I managed to get rid of a single error by copying in the generated file from a new project and changing:
#include "StdAfx.h"
to:
#include "stdafx.h"
I can't help but think this project was using StdAfx.h (there are about 150 references to it) for a reason, and that I shouldn't be adding a bunch of stdafx.h and stdafx.cpp files scattered around the place.
Is there some way of referencing a global stdafx.h file that was being used that could be causing this error?
In Windows, file names are not case-sensitive.
You can't expect that someone else stdafx.h file will be useful in your project. You need to find the original one.
Typically, one project uses one header file for precompiled header, shared by every source file that includes it.
I am working on a project that has a vendor-provided API. I've made a class that uses that API in my project and I've included the vendors header file in my stdafx.h file. Things would not compile.
I then put the #include directly into my class' header file and now things compile (And yes, my class includes stdafx.h so that isn't the reason.
Do any of you have any guesses as to why it wouldn't compile the first time around? This isn't a project-stopper by far but I'd prefer if I could keep all vendor API files in stdafx.h where they belong.
EDIT: Problem solved, I'd created a cyclic dependency by forgetting to #ifndef a header file and then including them in the wrong order. I feel like an idiot.
stdafx.h is mainly used in the VS generated projects as the 'container' of headers to be precompiled.
When you added a new #include to stdafx.h it didn't get included because your project is probably configured to use precompiled headers, and when you add something to stdafx.h you need to regenerate the .pch file that contains the precompiled information.
One way to do that is to have a .cpp file in your project that does nothing but #include "stdafx.h". Maybe call it `precompile.cpp". Then go to the project settings for that one .cpp file and change the following setting (for all configurations):
"C/C++ | Precompiled Headers | Precompiled Header" setting
and select "Create /Yc".
That will set up the build so that when precompile.cpp needs to be built (because the stdafx.h header it includes has changed), it'll rebuild the .pch file that everything else uses.
EDIT: Wait - I don't think I read the question right. May still be helpful, though.
Another name for stdafx.h is a 'Precompiled header'
There aren't really any 'vendor specifics' in stdafx.h, what it does is it precompiles headers so that the compiler doesn't have to re-compile them every time you build the project.
It's only really helpful if you have a huge project (or a small one that includes tonnes of headers).
I use visual studio 2010 as well, generally it's not worth the fuss - I just disable it (which would solve your class inclusion issue also - make your own header, stick the vendor's in there).